System and method for selecting a proof printer for a given production printer

ABSTRACT

A method for selecting a printing device for printing a proof is provided. The method entails providing a production printer and a plurality of remote proof printers and computing a native color gamut covered by the production printer and the plurality of remote proof printers. The method includes calculating a gamut intersection volume between the production printer and the plurality of remote proof printers and comparing the gamut intersection volume between the production printer and the plurality of remote proof printers. The method further include presenting a rating of the plurality of proof printers, the rating configured to provide data pertaining to the gamut intersection volume difference between each of the plurality of proof printers and the production printer.

BACKGROUND

The present disclosure relates to printing systems, more specifically,to a system and method for selecting a proof printer for a givenproduction printer.

Print buyers or document designers do not always have access to digitalproduction printers. As such, during the course of designing a documentfor subsequent printing using a production printer, the documentdesigner creates proofs for visualizing how a final, production printwill appear. These proofs are often created using any of a number ofprinters (DFE/IOT) more suitable for an office environment, such as adesktop inkjet device.

The created proofs generally set expectations for the designer or theprint buyer as to the colorimetric attributes and final appearance ofthe production print. When the designer or print buyer likes aparticular proof, an electronic application file corresponding to theparticular proof is then submitted to a press or other facility having aproduction printer for producing a production print corresponding to theproof. Upon submission, the operator of the press is requested to“match” the proof, especially the colorimetric attributes of the proof,with the production print such that the production print substantiallymatches the proof. The colorimetric attributes refer to parameters andaspects which affect the color rendition of a print, such as brightness,contrast and hue.

Typically, an operator of a production printer has two options. Oneoption is to explain to the designer or print buyer that the office ordesktop printer that was used to create the proof produces prints whichhave different colorimetric attributes than the colorimetric attributesof prints produced by the production printer, and therefore, thecalorimetric attributes of the print cannot be matched to thecalorimetric attributes of the proof. The second option for the operatorof the production printer is to use trial-and-error and attempt to setup the production printer with digital settings which would produce aproduction print which would more closely match the colorimetricattributes of the proof. This option requires the operator to spend timeand effort to set up the production printer in an effort to closelymatch the colorimetric attributes of the proof.

The second option can be fruitless as there are typically physicallimitations as to how close the color attributes can be matched. Forexample, the proof and the production print may have very differentphysical marking characteristics, e.g. inkjet versus toner, paper stock,and dye choices of colorants.

The operator of the production printer cannot usually make a “copy” ofthe proof, since the proof is likely to have lower IQ than what isavailable on the production printer (streaks, bands, error-diffusiondots, lower resolution, etc.), and may even be damaged (folded,scratched, etc.). There may also be document finishing options that areavailable in a “printer” mode, that are not available in a “copy” mode(e.g., signatures, imposition, slip sheets, tabs).

Additionally, even if the proof is not damaged, the operator of theproduction printer cannot simply scan the proof and use a visual displayof the scanned proof in order to produce the production print. This isdue to the different color spaces used by different devices. Forexample, the CMYK color space is the color space used for productionprinters and most color personal computer printers. The CMYK color spaceuses cyan, magenta, yellow and black inks on paper to absorb red, greenand blue light. The remaining reflected light is the color perceived bythe viewer. While the CMYK color space is the standard color space usedby production printers, the Red-Green-Blue (RGB) color space is apersonal computer's native color space.

Both RGB and CMYK color spaces are device-dependent color spaces; i.e.,the colors rendered depend on the device that produces the colors. Forexample, the calorimetric attributes produced by a scanner vary from thecalorimetric attributes visible on a monitor since a scanner uses a CCD(charge coupled device) array to capture colors, while a monitorproduces colors from light-emitting phosphors. Additionally, the processof converting an image from the RGB color space to the CMYK color spacegenerally compresses the colors into a smaller range.

The CMYK color space of one printer/device can vary significantly fromthe CMYK color space of another printer/device. Therefore, the CMYKcolor space of a first production printer can vary significantly fromthe CMYK color space of a second production printer. As such, ICC(International Color Consortium) profiles are frequently used to managecolor between devices.

An ICC profile is a computer file that describes the color capabilitiesand the color space of a particular monitor, scanner, printer, printingpress or color proofing device. ICC-based color management relies on twothings: (1) device profiles, which characterize how individual devicesproduce color, and a color engine (also called a color matching moduleor CMM), which reads those profiles and translates and corrects colorsbetween devices; and (2) LAB or XYZ calorimetric space, which arbitratesbetween color spaces of different devices. To simplify the discussion,we will only consider the LAB colorimetric space in the rest of thisapplication. LAB calorimetric space is based on the way the human eyeperceives color and is device independent. A LAB color engine translatesRGB, CMYK and other color spaces to and from LAB, that is, a LAB colorengine acts as an interpreter between different color spaces.

Most electronic documents to be printed or output on a particular deviceinclude multiple elements, such as text, photos, graphics and the like.Many electronic documents are a composite of other smaller documents andelements. For example, photos may be pasted into a large text documentat different locations. Color graphics and monochrome images may occuron the same page of a document.

Accordingly, the individual elements of an electronic document thattheir calorimetric attributes are to be matched may be represented in avariety of color spaces; a situation which arises because the elementsare derived from prior documents of differing origins. This situationmay not be immediately apparent to the user, because the colors andother colorimetric attributes of the objects appear to match on thedisplay or when printed using a straightforward color transformationprocess, such as is typical in ICC-based color management.

Currently, a remote proof can be created using an emulation mode on aremote proof printer. The emulation is performed by using the CMYKdestination profile of the production run printer. The digital front end(DFE) of the remote proof printer converts the CMYK or RGB of the PDLjob to the CMYK of the production run printer. This emulation CMYK isthen converted to the CMYK of the remote proof printer for printing. Ifthe gamut of the production and proof printer are significantlydifferent (not unusual) the print on the remote proof printer will notbe a good representation of the production run print.

Based on the above background information, there exists a need for asystem and method for selecting the optimal proof printer for a givenproduction printer.

SUMMARY

According to the present disclosure a method for selecting a printingdevice or proof printer for printing a proof is provided. The methodincludes providing a production printer and a plurality of proofprinters and computing a native color gamut covered by the productionprinter and each of the plurality of proof printers. The method alsoincludes calculating a gamut intersection volume between the productionprinter and each of the plurality of proof printers and comparing thegamut intersection volume between the production printer and each of theplurality of proof printers. The method further includes presenting arating of the plurality of proof printers, the rating configured toprovide data pertaining to the gamut intersection volume differencebetween each of the plurality of proof printers and the productionprinter.

The present disclosure also provides a system for selecting a printingdevice or proof printer for printing a proof. The system includes aproduction printer, a plurality of proof printers and applicationsoftware configured to manage the flow of print jobs to the plurality ofproof printers. The system further includes at least one processorcapable of executing the application software for computing a nativecolor gamut covered by the production printer and each of the pluralityof proof printers; calculating a gamut intersection volume between theproduction printer and each of the plurality of proof printers;comparing the gamut intersection volume between the production printerand each of the plurality of remote proof printers; presenting a ratingof the plurality of proof printers, the rating configured to providedata pertaining to the gamut intersection volume difference between eachof the plurality of proof printers and the production printer; andselecting one of the plurality of proof printers for printing the proofbased on the rating.

The present disclosure further provides a computer-readable storagemedium storing a set of programmable instructions capable of beingexecuted by at least one processor for performing the method of:computing a native color gamut covered by a production printer and eachof a plurality of proof printers; calculating a gamut intersectionvolume between the production printer and each of the plurality of proofprinters; comparing the gamut intersection volume between the productionprinter and each of the plurality of proof printers; and presenting arating of the plurality of proof printers, the rating configured toprovide data pertaining to the gamut intersection volume differencebetween each of the plurality of proof printers and the productionprinter.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present disclosure will be described hereinbelow with reference to the figures wherein:

FIG. 1 is a flow chart illustrating a method in accordance with thepresent disclosure;

FIG. 2 is a flow chart illustrating a portion of the method of thepresent disclosure; and

FIG. 3 is a diagram illustrating a system in accordance with the presentdisclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described herein belowwith reference to the accompanying drawings. In the followingdescription, well-known functions or constructions are not described indetail to avoid obscuring the present disclosure in unnecessary detail.

The word “printer” and terms “printing system”, “proof printers” and“remote proofers” as used herein encompass any apparatus and/or system,such as a digital copier, xerographic and reprographic printing systems,bookmaking machine, facsimile machine, multi-function machine, etc.which performs a print outputting function for any purpose.

Referring to FIG. 1 a method for selecting a printing device or proofprinter for printing a proof in accordance with the present disclosureis shown. The method includes providing a production printer and aplurality of remote proof printers or remote proofers (STEP 101). Theplurality of remote proof printers may be used in conjunction with anetwork having a server and a series of client side devices operativelyconnected thereto.

The method also includes computing the native color gamut covered by theproduction printer and each of the plurality of remote proof printers(STEP 102). The native (non-emulation modes) CMYK color gamut covered bya printer class is computed using a spectral data application (SDA). Itis envisioned that the gamut information may be shipped within the DFEcode for each print engine. Alternatively, the gamut information couldbe stored in a memory device such as, for example, floppy disks, CD-ROM,flash-drives, hard drives, DVD, RAM, memory cards, diskettes, smartcards etc. Moreover, the gamut information could also be shipped ordownloaded to a process manager which is described in greater detailhereinbelow.

The SDA is capable of receiving spectral data and converting it intocolor space data. Information regarding spectral data provides the mostcomplete and precise means of describing a color, by specifying theamount of each wavelength that the sample reflects. Spectral datarecords the amount of reflected light, typically, in 10-nanometer or20-nanometer bands. Furthermore, the SDA may also analyze specific colorspace data (e.g. color space volume, color space volume within a sliceof the color space etc.). The SDA is configured to perform comparativeoperations such as computing volume differences between printer colorspaces.

The process manager may be a client application (based on PDFs). Themanager may reside in the print shop and could be configured to accessany printer on the network. It is envisioned that the process managercould be utilized to route jobs to particular printers and to automateworkflow in a shop. Moreover, jobs could be routed to appropriateprinters based on standards or rules (e.g. print on a remote printerthat fits, for a color perspective, the production printer). Theworkflow can be stopped for human intervention at defined “nodes”. Forexample, one node could be a review step for choosing an appropriateproof device or for human review of the proof before initiating theproduction job.

The gamut intersection volume, for the production and each of the remoteproof printers, is computed (STEP 103). The intersection volume issubtracted from the gamut volume of the production printer. Thedifference is the color space volume of the production printer that theremote proofer cannot reproduce.

If the volume difference value is zero, the remote proofer can reproduceall the colors of the production printer. If this is the case the useris informed, through a graphical user interface, that his/her selectionof remote proofer is optimal for gamut. For volume differences greaterthan zero, the user is advised that the remote proofer will not coverall the colors that the production printer is capable of producing. Oncethe volume differences are computed, the gamut intersection volumebetween the production printer and each of the plurality of remote proofprinters may then be compared (STEP 104).

The method of the present disclosure further includes a ratings systemthat rates the gamut volume shortfall of each of the remote proofers.The rating is configured to provide data pertaining to the gamutintersection volume difference between each of the remote proof printersand the production printer (STEP 105). For example, the gamut volumeshortfall may be insignificant (small volume difference), significant(moderate volume difference) or unacceptable (large volume difference).Determinations on what constitutes a certain rating can be obtained frompast testing results or customer studies. For each of these differencelevels, the user is given the option to search for “a better gamut fit”.If the user selects this option, the user is then asked if the gamuts tobe used for comparison should be process manager stored gamuts, gamutsfrom accessible printers or both. The remote proof printer candidate(s)with the smallest gamut volume difference numbers are presented to theuser as the optimal gamut choice(s). The user can then select theoptimal gamut fitting remote proofer (i.e. proof printer). It isenvisioned that the user could be shown the visually the gamutdifferences.

The gamut difference rating can be extended to use weighting factors fordifferent regions/sections of color space. For example, equal volumedifferences in light colors and dark colors may be rated differently.The light color volume differences could be weighted higher (moreobjectionable) than darker volume differences. Other weightings could beapplied to various hue volumes (e.g. green differences are lessobjectionable than red differences). The weightings could be hard-codedin by engineering testing or adjustable by a customer's preferences.

If the color space values are computed in CIELAB, the color differenceformula CIE ΔE₉₄ could be used to compute the volume differencerating/number. The difference in minimum ΔE₉₄ between the gamut surfacepoints of the bigger gamut (at least for one region of color space)production printer and the gamut surface points of the smaller gamutremote could be computed. The computation would be for a defined densityof nodes on the bigger production gamut surface. An outlying point onthe big surface would be given the value of the smallest ΔE₉₄ differenceto a point lying on the smaller gamut surface. The process would berepeated for points across the outlying production gamut surface. Thevalues for the point would be added up resulting in a rating number.

It is envisioned that the present disclosure could enable users todetermine the optimal fitting remote proof printer for certain specificsections of gamut (e.g., yellow hue colors, dark reds, dark colors,etc.). The gamut volume of a printer would need to be divided intoappropriate volume sections for comparison to the production printer'sequivalent color section. For example, a document may have a lowcompatibility between red and green colors but a high compatibilitybetween blue colors.

Referring to FIG. 2, if the remote proof option within the processmanager is invoked the user is asked if he/she wants to use the optimalgamut fit tool (STEP 201). If yes, the user is asked to specify at leastone of the following:

-   -   1. The printer type for both the production printer and the        remote proof printer (STEP 202). The process manager will use        locally stored gamut information (STEP 202 a);    -   2. The actual printer for both the production printer and the        remote proof printer (STEP 203). This may have more up-to-date        gamut information than that stored in the process manager. The        process manager will use remotely stored gamut information (STEP        203 a); and/or    -   3. The production printer only (STEP 204). In which case the        user will be given advice on the best gamut fit from the proofer        gamuts stored on process manager or the printers, with stored        gamuts, accessible by the process manager. It is envisioned that        the process manager may use remote or locally stored gamut        information (STEP 204 a).

Once the printer information is provided in one of the aforementionedsteps, the user is presented with the printer that is the best gamut fit(STEP 205). It is contemplated that the best gamut fit may be presentedin conjunction with a ratings system as described herein.

These techniques may be used in accordance with a system 300 forchoosing the optimal printing device for a remote proof. System 300includes a production printer 301 and a plurality of remote proofprinters 302, 304 and/or 306. System 300 further includes applicationsoftware 308 configured to manage the flow of print jobs to each of theplurality of proof printers 302, 304 and 306. The application software308 could be housed within a client side PC, inside or outside a printeror on a computer readable storage medium such as a CD-ROM. Theapplication software may include gamut information pertaining toproduction printer 301 and/or any or all of the remote proof printers302, 304 or 306. Although three proof printers are shown in thisembodiment, it is envisioned that any number of proof printers could beused.

System 300 may further include at least one processor 310 having amemory configured to perform the following steps: executing theapplication software 308 for computing a native color gamut covered byproduction printer 301 and the plurality of remote proof printers 302,304 and 306; calculating a gamut intersection volume between productionprinter 301 and the plurality of remote proof printers 302, 304 and 306;comparing the gamut intersection volume between production printer 301and the plurality of remote proof printers 302, 304 and 306; andpresenting a rating of the plurality of remote proof printers 302, 304and 306, the rating configured to provide data pertaining to the gamutintersection volume difference between each of the plurality of remoteproof printers 302, 304 and 306 and production printer 301. Processor310 may be operatively connected to a graphical user interface (GUI) 312for presentation of the rating and/or selection of the optimal printingdevice. The rating may be based on differential weightings of the colorspace region.

It is envisioned that the application software may utilize either remoteor locally stored gamut information. The application software utilizedin accordance with the present disclosure, for example, may be locatedentirely on the client side. This could provide total analysis from aremote location and eliminates the need for a system administrator. Thenative color gamut information may be stored within a print engine. Thetechniques and devices described herein may be used entirely orpartially on a network.

The techniques of the present disclosure may be hosted on a range ofdifferent client machines, e.g., the machine hosting the printsubmission client, the machine hosting an output management system, oran entirely different client side machine. This disclosure is intendedto encompass all of these possible variations.

The aforementioned techniques may be used with a computer-readablestorage medium storing a set of programmable instructions capable ofbeing executed by at least one processor for performing the method of:computing a native color gamut covered by a production printer and aplurality of proof printers; calculating a gamut intersection volumebetween the production printer and the plurality of proof printers;comparing the gamut intersection volume between the production printerand the plurality of proof printers; and presenting a rating of theplurality of proof printers, the rating configured to provide datapertaining to the gamut intersection volume difference between each ofthe plurality of proof printers and the production printer. Thecomputer-readable storage medium may include, but is not limited to,floppy disks, CD-ROM, flash-drives, hard drives, DVD, RAM, memory cards,diskettes, smart cards etc.

Many of the aforementioned techniques may be used to consider the shapeof missing gamut or calculate the maximum gamut error for a certainproof. The techniques described above could be used to calculate thefrequency of use of missing colors. Moreover, color difference metricssuch as CIE ΔE₉₄ or ΔECMC could be used to describe the gamut shortfallsin terms of color perception (e.g. less able to perceive differences indark blues vs. yellows).

It will be appreciated that variations of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. It isenvisioned that the claims can encompass embodiments in hardware,application software or a combination thereof. Various presentlyunforeseen or unanticipated alternatives, modifications, variations orimprovements therein may be subsequently made by those skilled in theart which are also intended to be encompassed by the following claims.

1. A method for selecting a printing device for printing a proof, themethod comprising: providing a production printer and a plurality ofproof printers; computing a native color gamut by using a spectral dataapplication, the gamut covered by the production printer and theplurality of proof printers, and including gamut information processedby a process manager, where the process manager is configured to operatebased on one or more preset standards or preset rules; calculating agamut intersection volume between the production printer and theplurality of proof printers via the spectral data application, whereinthe spectral data application receives spectral data and converts thespectral data into color space data to specify an amount of eachwavelength that a sample reflects; comparing the gamut intersectionvolume between the production printer and the plurality of proofprinters; assigning a rating related to the plurality of proof printers,the rating configured to provide data pertaining to the gamutintersection volume difference between each of the plurality of proofprinters and the production printer, wherein said rating use weightingfactors for a different region, a different section of color space, anda hue volume; and allowing a user to search and select one or moregamuts for each assigned rating, the one or more gamuts provided by theprocess manager or the plurality of proof printers.
 2. The methodaccording to claim 1, wherein the native color gamut is CMYK.
 3. Themethod according to claim 1, further comprising the step of: includingthe native color gamut within a print engine of one of the plurality ofproof printers.
 4. The method according to claim 1, further comprisingthe step of: dividing the gamut volume of each of the plurality of proofprinters and the production printer into sections.
 5. The methodaccording to claim 4, further comprising the step of: comparing thesections to determine an optimal proof printer of the plurality of proofprinters for certain sections of gamut.
 6. The method according to claim1, further comprising the step of: determining whether the gamuts usedfor the step of comparing are client application stored gamuts, gamutsfrom the plurality of proof printers, gamuts from the production printeror gamuts from both the plurality of proof printers and the productionprinter.
 7. The method according to claim 1, wherein the step ofassigning a rating includes ranking each proof printer based upon thedifference between the gamut volume of the production printer and itsrespective intersection volume.
 8. The method according to claim 1,further comprising the step of considering at least one of the shape ofmissing gamut, the maximum gamut error and the frequency of use ofmissing colors.
 9. The method according to claim 1, wherein the spectraldata application receives spectral data and converts the spectral datato color space data.
 10. The method according to claim 9, wherein thespectral data includes an amount of each wavelength that the proofreflects.
 11. The method according to claim 9, wherein the spectral datarecords an amount of light reflected from the proof.
 12. The methodaccording to claim 9, wherein the spectral data records an amount oflight reflected, wherein said amount of light reflected is in the 10nanometer band or the 20 nanometer band.
 13. The method according toclaim 1, wherein the process manager routes jobs to a particular printerand automates workflow in a shop.
 14. The method according to claim 1,wherein the rating indicates a gamut volume shortfall of each remoteproof printer.
 15. The method according to claim 1, further comprisingcomputing a color difference formula CIE ΔE₉₄ to compute the volumedifference, wherein the volume difference comprises a minimum ΔE₉₄between the gamut surface points of a larger gamut production printerand a gamut surface points of the smaller gamut, wherein an outlyinggamut surface point on a larger gamut surface is assigned a value of asmallest ΔE₉₄ difference to a point lying on the smaller gamut surface.16. A system for selecting a printing device for printing a remoteproof, the system comprising: a production printer; a plurality ofremote proof printers; a network connecting the production printer andthe plurality of proof printers; application software configured tomanage the flow of print jobs to the plurality of proof printers; and atleast one processor capable of executing the application software forcomputing: a native color gamut by using a spectral data application,the gamut covered by the production printer and the plurality of proofprinters, and including gamut information processed by a processmanager, where the process manager is configured to operate based on oneor more preset standards or preset rules; calculating a gamutintersection volume between the production printer and each of theplurality of proof printers via the spectral data application, whereinthe spectral data application receives spectral data and converts thespectral data into color space data to specify an amount of eachwavelength that a sample reflects; comparing the gamut intersectionvolume between the production printer and each of the plurality of proofprinters; assigning a rating related to the plurality of proof printers,the rating configured to provide data pertaining to the gamutintersection volume difference between each of the plurality of proofprinters and the production printer, wherein said rating use weightingfactors for a different region, a different section of color space, anda hue volume; and allowing a user to search and select one or moregamuts for each assigned rating, the one or more gamuts provided by theprocess manager or the plurality of proof printers.
 17. The systemaccording to claim 16, wherein the rating is based on a region of colorspace that is not covered by the plurality of proof printers.
 18. Thesystem according to claim 16, wherein the native color gamut is CMYK.19. The system according to claim 16, wherein the native color gamut isincluded within a print engine.
 20. The system according to claim 16,wherein the application software utilizes one of remote and locallystored gamut information.
 21. A computer-readable non-transitory storagemedium storing a set of programmable instructions capable of beingexecuted by at least one processor for performing the method of:computing a native color gamut by using a spectral data application, thegamut covered by the production printer and the plurality of proofprinters, and including gamut information processed by a processmanager, where the process manager is configured to operate based on oneor more preset standards or preset rules; calculating a gamutintersection volume between the production printer and the plurality ofproof printers via the spectral data application, wherein the spectraldata application receives spectral data and converts the spectral datainto color space data to specify an amount of each wavelength that asample reflects; comparing the gamut intersection volume between theproduction printer and each of the plurality of proof printers;assigning a rating related to the plurality of proof printers, therating configured to provide data pertaining to the gamut intersectionvolume difference between each of the plurality of proof printers andthe production printer, wherein said rating use weighting factors for adifferent region, a different section of color space, and a hue volume;and allowing a user to search and select one or more gamuts for eachassigned rating, the one or more gamuts provided by the process manageror the plurality of proof printers.
 22. The computer-readablenon-transitory storage medium according to claim 21 further comprisingthe step of: including the native color gamut within a print engine ofone of the plurality of proof printers.
 23. The computer-readablenon-transitory storage medium according to claim 21 further comprisingthe step of: comparing the sections to determine an optimal proofprinter of the plurality of proof printers for certain sections ofgamut.
 24. The computer-readable non-transitory storage medium accordingto claim 21 wherein the step of assigning a rating includes ranking eachproof printer based upon the difference between the gamut volume of theproduction printer and its respective intersection volume.
 25. Thecomputer-readable non-transitory storage medium according to claim 21further comprising the step of: determining the rating using a colordifference computation.